Photodefinable dielectric composition useful in the manufacture of printed circuits

ABSTRACT

A composition and process useful in fabricating circuitry packages with permanent resists is proposed. The proposed composition comprises a carboxy functional resin, an acrylate oligomer, an epoxy functional resin, a butadiene nitrile resin, and a photoinitiator.

This application is a continuation-in-part of U.S. patent applicationNo. 08/412,286, U.S. Pat. No. 5,545,510, which was filed on Mar. 28,1995.

FIELD OF THE INVENTION

The present invention relates to a composition useful in the manufactureof printed circuits of various types. In particular, the composition ofthe present invention is useful in creating a photodefinable dielectricsurface which is platable with acceptable adhesion. The composition isuseful as a permanent photodefinable dielectric. As used herein"permanent resist" shall mean a permanent photodefinable dielectric.

BACKGROUND OF INVENTION

Printed circuit boards utilize a variety of resists in theirmanufacture. Typically the resists used are of a temporary ornon-permanent type, meaning that the resist is used to create an imageand then is later stripped from the surface. Various resists of thistype are known and used in the art.

Printed circuit board designs using "permanent resists" are also known.A permanent resist is one which is used to create an image on a surfaceof the printed circuit board and then remains as an integral part ofthat surface (i.e. is not stripped away). Permanent resists used in themanufacture of printed circuit boards are described in U.S. Pat. No.3,982,045 issued Sep. 21, 1976 to Kukanskis, the teachings of which areincorporated herein by reference in their entirety. In addition see U.S.Pat. No. 4,882,245 issued to Gelorme et al, the teachings of which areincorporated herein by reference in their entirety. Also see U.S. Pat.Nos. 5,246,817 and 5,322,976, the teachings of which are incorporatedherein by reference in their entirety. Shanefield et al., in U.S. Pat.No. 4,444,848, the teachings of which are incorporated herein byreference in their entirety, describes a modified epoxy material whichplates with improved adhesion.

Attempts to manufacture useful permanent resists and printed circuitboards and packages using such resists have uncovered a number ofdifficulties. For a discussion of soldermasks and their compositionsplease refer to U.S. Pat. No. 5,296,334, the teaching of which areincorporated herein by reference in their entirety. Among the problemsexperienced are poor adhesion of the resist to the surface, particularlywhen temperature cycling is taken into consideration, inability toobtain suitable photodefmability of the resist, poor adhesion ofsubsequent metal platings to the surface of the resist, inability of theresist to withstand processing in the various subsequent processingchemicals, and/or inability of the resist to provide the appropriatedielectric properties necessary.

A permanent resist formulation and process which answered most or all ofthe above cited drawbacks would prove very beneficial in the fabricationof printed circuit boards, surface laminar circuitry packages and otherimportant devices. Surface Laminar Circuitry CSLC) is a techniquewhereby glass/epoxy laminate, or other substrates such as copperlaminates, polyimides and polyetherimides, and a permanent resist areused to produce a structure resembling that of a semiconductorintegrated circuit. This technology represents a change in the designconcept of multilayer boards, and was developed to meet the requirementscaused by the increasing rise of surface mounted devices for highresolution boards with high terminal pitch and enhanced wiringcapability. It is an object of the current invention to provide such apermanent resist formulation and process.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to overcomedisadvantages of the prior art. It is another object of the invention toprovide a composition which is photodefinable into a permanent resist(i.e. permanent photodefineable dielectric) which has good adhesionproperties both to the surface below it and to the metal subsequentlyplated onto it. It is yet a further object of the invention to provide apermanent photodefineable dielectric surface which is compatible withvarious plating solutions and therefore provides improved coverage andplatability when plated upon. It is a further object of the currentinvention to present a composition which is useful as a permanentphotodefineable dielectric on printed circuit boards, surface laminarcircuitry packages, and other circuitry packages. Finally it is a stillfurther object of the current invention to develop a permanentphotodefineable dielectric which is capable of imagewise curing orpartial curing in response to imagewise photo-radiation exposure andsubsequent development in an aqueous medium. (e.g. alkali metalcarbonate solution in water).

These and other objects are accomplished by the present invention which,in one aspect, is a photocurable composition comprising:

(a) at least one carboxy functional resin;

(b) at least one acrylate oligomer;

(c) at least one epoxy functional resin;

(d) at least one butadiene nitriffle resin which may optionally becarboxy terminated;

(e) a photo-initiator which is optionally non-sulfur bearing; and

(f) optionally filler.

As used in this specification and in the claims butadiene nitrile resinshall be interpreted as meaning, copolymers of butadiene withacrylonitrile and derivatives thereof but excluding terpolymers such asacrylonitrile-butadiene-styrene. Derivatives of copolymers of butadienewith acrylonitrile shall include all types of reactive end cappedcopolymers of butadiene with acrylonitrile such as epoxy terminated,acrylic terminated, carboxy terminated, amino terminated, vinylterminated and the like.

In another aspect, the present invention relates to the use of the aboveindicated composition as a permanent photodefineable dielectric indefining circuitry and vias in the following process:

(a) coating said composition onto a substrate;

(b) exposing the coating on the substrate to an imagewise pattern ofradiation to which the composition is responsive in an mount sufficientto at least partially cure the composition;

(c) developing the exposed composition with a solution which willdissolve the non-exposed areas of the coating; and

(d) optionally further curing the coating which remains on thesubstrate;

(e) optionally repeating steps (a)-(d);

(f) depositing a conductive material on at least those portions of thesubstrate which are not covered by the developed imagewise coating so asto form defined circuits and or interconnects on the surfaces, ordepositing a conductive material onto the entire surface of thesubstrate and subsequently defining circuits and interconnects byetching away defined portions of the conductive material.

(g) Optionally repeated steps (a)-(e) so as to build several layers ofcircuitry.

DETAILED DESCRIPTION OF THE INVENTION

It has been discovered that when the composition of the presentinvention is used as a permanent photodefineable dielectric in circuitpackages, such as printed circuit boards, various advantages areachievable over the prior art. Firstly, the permanent photodefineabledielectric formulation of the current invention provides good adhesionof the photodefineable dielectric to the surface to which it is applied.This adhesion is suitable such that delamination of the dielectric fromthe surface does not occur even after repeated temperature cyclings.

Secondly, the resist formulation of the current invention isphotodefinable by imagewise exposure to photo-radiation and subsequentdevelopment in aqueous solution. Thus the current invention is solubleor developable in aqueous alkaline solutions, such as a solution ofalkali metal carbonate and water. Heretofore, many resist formulations,particularly permanent resist formulations, were developable only inobjectionable solvents and solvent mixtures. Thus developability in anaqueous media provides definite advantages over solvent developabilitybecause of environmental, safety and cost concerns associated with theformer solvents.

Thirdly, this permanent photodefineable dielectric formulation providesfor excellent adhesion of plated metal to its surface. Thischaracteristic of the present formulation is of particular importance.Thus in the past it has been difficult to obtain good metal to permanentresist adhesion while retaining other important dielectric andfunctional features. This invention, however, provides a permanentphotodefineable dielectric that retains all the generally desiredphysical properties or resist features while providing excellent platedmetal to dielectric adhesion. Adhesion of the plated metal to thepermanent resist is typically in the range of 6 lbs/in. In additionthese adhesion values are maintained even after temperature cycling suchas solder shock for 10 seconds at 288° C. which is the standard testprocedure in this industry. Coverage of the plated metal upon or nearthe permanent resist is also excellent. Although not wishing to be boundby theory, the inventors believe that the presence of the butadienenitrile resin, particularly carboxy terminated and most preferably epoxyterminated, in the formulation provide for excellent plated metal todielectric adhesion. In addition, the addition of fumed silica to thephotodefineable permanent dielectric formulation also improves platedmetal to dielectric adhesion. Other specific parameters of theformulation and the plating cycle also assist in increased adhesion ofthe plated metal to the surface.

Fourthly, this permanent photodefineable dielectric formulation isgenerally resistant to subsequent chemical processing. Thus thedielectric and all its properties remain in tact even after thenecessary subsequent processing, chemical, thermal and mechanical.

Finally, this permanent photodefineable dielectric formulation providesexcellent dielectric properties which allow it to act as the soleseparator between circuit traces in the x, y and z planes. Thusdielectric constants of 3.30 to 3.50 are achievable with the permanentphotodefineable dielectric formulation of the current invention. Thusthis invention proposes the formulation of a permanent photodefineabledielectric with desireable properties such as hardness, dielectricproperties, resist integrity through and after processing, resist tosurface adhesion and plated metal to resist adhesion.

All of the above recited advantages and others are therefore achievableby utilizing a permanent resist formulation comprising:

(a) at least one carboxy functional resin;

(b) at least one acrylate oligomer;

(c) at least one epoxy functional resin;

(d) at least one butadiene nitrile resin which may optionally be carboxyterminated, preferably epoxy terminated;

(e) a photoinitiator which is optionally a non-sulfur beatingphotoinitiator;

(f) optionally a filler; and

(g) at least one reactive monomer, which is preferably an acrylatemonomer.

The carboxy functional resin of the proposed resist formulation can beany one or several of various known types such as Morez 100 or 200styrene acrylic carboxy functional copolymers--available from MortonInternational, Carboset 527, 526 or 1160 --carboxy functional acryliccopolymers--available from B. F. Goodrich Company, or Scripset 550, or560 available from Monsanto Company. The inventors have found Carboset526 to be particularly useful in formulating the permanentphotodefineable dielectric formulation of this invention. Theconcentration of the carboxy functional resin in the final permanentresist formulation can range from 2 to 50 weight percent, but ispreferably at 5 to 25 weight percent and most preferably at 10 to 15weight percent.

The acrylate oligomer used in the current invention can consist of anyone or several of various known acrylate oligomers, such as CN961E75,CN972, CN120A75, CN120C80, Pro-1100, or Sarbox 350, 400 or 401 --styrenemaleic anhydrides ester of hydroxyethyl methacrylate--all available fromthe Sartomer Company. The inventors have found Pro-1100 to beparticularly useful in formulating these proposed permanentphotodefineable dielectric formulations. The concentration of theacrylate oligomer in the final formulation can range from 20 to 50weight percent, but is preferably 25 to 40 weight percent and mostpreferably 30 to 40 weight percent.

The epoxy functional resin useful in these proposed permanent resistformulations may consist of any one or several epoxy resins such as thefollowing: ECN 1280 or 1299 --Epoxy Cresol Novolac --available fromCiba-Geigy Corporation or Epulon N695, Epon 500×8 and Epon 872 availablefrom Shell Corporation. The inventors have found ECN 1299 to beparticularly useful in formulating the material proposed by thisinvention. The concentration of the epoxy resins useful herein in theseformulations may range from 20 to 50 weight percent, but is preferablyfrom 25 to 45 weight percent and most preferably from 30 to 40 weightpercent.

Several butadiene nitriffle resins (including a variety of copolymers ofbutadiene and acrylonitrile) are useful in the formulations of thisinvention, including: Hycar 1300 X 8, 1300 X 13 or 1300 X 31 allavailable from B. F. Goodrich Company.

The inventors have found Hycar 1300 X 8 to be a particularly usefulcarboxy terminated butadiene nitrile resin in the formulations of thecurrent invention. The concentration of the butadiene nitrile resin inthe final formulation should range from 1 to 10 weight percent, but ispreferably from 2 to 6 weight percent and most preferably from 3 to 5weight percent. It is preferable for the butadiene nitrile resin to be acarboxy terminated butadiene nitrile resin. In the most preferredembodiment of this invention, the carboxy terminated butadiene nitrileresin is an epoxy terminated butadiene nitrile resin. It is believedthat epoxy terminated butadiene nitrile resins provide additionalflexibility, improved dielectric properties, and enhanced durability tothese resist formulations in comparison to resist formulations usingother carboxy terminated butadiene nitrile resins. With that said, avariety of copolymers of butadiene with acrylonitrile are useful in theformulations of this invention including such copolymers of butadienewith acrylonitrile with one or more reactive ends such as epoxyterminated, carboxy terminated, acrylic terminated, amino terminated,vinyl terminated, and the like.

Although many photoinitiators can usefully be applied in the formulationof this invention, the inventors have discovered that non-sulfur bearingphotoinitiators provide advantages in the platability of the resist.Thus the current invention in its most preferred form, proposes aformulation which comprises only non-sulfur bearing constituents,particularly non-sulfur bearing photoinitiators. The non-sulfur bearingphotoinitiators may take one or several known forms such as:

Benzoin ethers, alphahydroxy dialkylacetophenones, acyl phosphines,cyclic benill deravitives, 3-Ketocoumerins, Quinones, Michler's Ketone,and Xanthone.

The inventors have found cyclic benzil derivatives to be a particularlysuitable non-sulfur beating photoinitiator as used in this invention.The concentration of the non-sulfur bearing photoinitiator in the resistformulation may range from 2 to 15 weight percent, but is preferablyfrom 4 to 12 weight percent and most preferably from 8 to 10 weightpercent. It is believed that non-sulfur bearing photoinitiators,particularly non-divalent sulfur bearing photoinitiators, provideadvantages in the platability of the resin. The inventors discoveredthat sulfur bearing photoinitiators were incompatible with andinterfered with the plating action of many plating baths when thosebaths were used to plate upon the surface of or near the surface of thepermanent photodefineable dielectric which used such sulfur bearingphotoinitiators. The permanent photodefineable dielectric formulation ofthe present invention answers these needs. Non-sulfur bearing as usedherein shall mean a composition and/or photoinitiator which does notcontain divalent or elemental sulfur.

Optionally, the formulations of the current invention may also containfiller materials such as silica. The inventors have discovered that theuse of fumed silica, as opposed to other forms of silica such asamorphous silica, provides advantages. In particular the use of fumedsilica as a filler in these compositions provides for improved adhesionof the plated metal to the surface of the resist as compared tocompositions with amorphous silica. If used, the concentration of fillerin these resist formulations may range from 0.5 to 5 weight percent, butis preferably from 1 to 2 weight percent and most preferably from 1 to 2weight percent. As indicated above, the most preferred embodiment ofthis invention utilizes fumed silica as the filler material.

The reactive monomer of the current invention should be capable ofundergoing cross-linking with the remainder of the formulation.Preferably the reactive monomer is a multifunctional acrylate ormultifunctional methacrylate monomer. These may include one or severalof various known compounds such as polyacrylates, polymethacrylates,1,6-hexane diol diacrylate, acrylate esters of bisphenol-A basedepoxies, tetraethylene glycol diacrylate and the like. The choice of anyparticular such compound or mixtures thereof will largely be dictated byreactivity for the (meth)acrylate groups on the esterified styrenemaleicanhydride copolymer, desired viscosity properties and the like.

In addition to the materials addressed above, other standard additivesmay also be included in the permanent resist composition of thisinvention. These additional additives include dyes, colors, flowmodifiers, antifoams and other known additives.

In the most preferred embodiment, the formulation is separated into twoparts which are mixed prior to use. Part A will contain all of theproposed components except for epoxy functional resin. Part B willcontain those components missing from Part A. This procedure ofseparating the materials is recommended for extended shelf-life of theproduct.

As indicated this invention is particularly useful as a permanentphotodefineable dielectric composition in fabricating printed circuitboards, surface laminar circuitry packages and other circuitry packages.As used in this manner the following process is proposed:

(a) coating said composition onto the surface of a substrate;

(b) exposing the coating to an imagewise pattern of radiation to whichthe composition is responsive in an amount sufficient to at leastpartially cure the composition;

(c) developing the exposed composition with a solution which will removethe non-exposed areas of the coating;

(d) optionally further curing the coating which remains on thesubstrate;

(e) optionally repeating steps (a)-(d);

(f) depositing a conductive material on at least those portions of thesubstrate which are not covered by the developed imagewise coating so asto form defined circuits and interconnects or depositing a conductivematerial onto the entire surface of the substrate and subsequentlydefining circuits and interconnects by etching away defined portions ofthat conductive material.

(g) Optionally repeating steps (a)-(f) so as to build several layers ofcircuitry.

As used herein interconnect shall mean an electrical connection betweenlayers of circuitry.

In the proposed process, the permanent photodefineable dielectriccomposition may be coated onto the surface of the substrate in a varietyof ways, including screening, roller coating, curtain coating,laminating, and spray coating, among others. The viscosity of thecomposition may be adjusted to suit the coating method and coatingthickness desired.

After coating, the composition is photodefined by exposing the coatedsurface to an imagewise pattern of radiation. The radiation most usefulin this manner is ultraviolet radiation, but other wavelengths ofradiation may be used. Thus in the preferred embodiment of thisinvention the composition proposed, once coated, is subjected toimagewise ultraviolet radiation in an amount sufficient to partiallycure the composition where it has been exposed.

The coated, exposed composition is then developed using a solution whichselectively removes the non-exposed areas of the coating. One particularadvantage of these proposed resist formulations is that they aredevelopable in aqueous solution as opposed to environmentally unsafe,hazardous and objectionable solvents. Thus in the preferred embodimentof this invention, the coated, exposed composition is developed in anaqueous solution of sodium or potassium carbonate, such that only theunexposed areas are removed from the surface.

After development it is typical to further cure the resist compositionwhich remains on the surface. As such, this additional curing isaccomplished by additional exposure to heat and/or photo-radiation.

Finally the process proposes that a conductive material be depositedupon at least those portions of the substrate which are not covered withthe resist. Thus it is proposed that plating can occur on only thoseareas where the resist has been removed (additive production of thecircuits), on the entire surface including areas where the resist wasremoved by development as well as upon the resist itself (subtractiveproduction of the circuits) or some degree of plating falling betweenthese extremes (semi-additive production of the circuits). For adiscussion of the specifics of circuitry and interconnect creation seeU.S. Pat. No. 4,847,114 (Brasch et. al.), the teachings of which areincorporated herein by reference in the entirety.

If the additive process is chosen at this point, then plating will occurin those areas where the permanent photodefineable dielectric has beenremoved by development and upon the surface of the dielectric in adefined manner such that defined circuitry and interconnects arecreated. Thus, the plating itself will define the circuitry and otherfeatures desired. In the additive process the photodefinition of thepermanent dielectric will create and define the circuitry and othersurface features desired as well as the holes and vias which willinterconnect the various layers of the circuitry package. If subtractiveprocessing is chosen then the entire surface will be plated. Thecircuitry and other features will be defined by subsequent etching ofthe plated metal. In the subtractive manner, the photodefinition of thepermanent resist will typically be used for the creation of holes andvias which connect the various layers of the circuitry package.

This brings out an additional advantage of the proposed composition andprocess. Because of its permanent nature, the resist of this inventionis useful notably in defining not only circuitry and surface features ofthe circuitry package but also the holes and vias used to interconnectthe layers of circuitry in the package. In addition, this permanentphotodefineable dielectric is used to separate the circuitry in allthree spacial directions. Because of its ability (due to dielectric andother properties) to separate and insulate the circuitry within a layerand from layer to layer, this permanent resist can be used tophoto-define the holes of the circuitry package. Photolithography ispreferred to mechanical drilling (the typical method of creating holesand vias) because smaller holes and vias can be created, and the holesand vias are formed and processed with greater ease and economy, ingeneral, as compared to mechanical drilling. Holes and vias as small as1.0 mil in diameter can be created.

Whichever type of processing is chosen (additive, substractive, orsemi-additive), the surface plating can be accomplished in several ways.The most typical way is the use of known electroless plating techniquesto plate either copper, nickel, or some other appropriate metal onto thedesired surface. These techniques may include chemical roughening of thesurface, conditioning, activation, acceleration and electroless plating.All of these steps are generally known and are described in U.S. Pat.Nos. 4,976,990 (Bach et. al.) and 4,834,796, the teachings both of whichare incorporated herein by reference in their entirety.

Other methods of depositing metals onto the desired surfaces are knownand may be utilized. These include direct metalization techniques suchas those described in U.S. Pat. No. 4,724,005 (Minten el. al.), theteachings of which are incorporated herein by reference in theirentirety. As an alternative, chemical vapor deposition may be utilized,in addition to a variety of other known methods for metal depositionupon non-conductive surfaces.

The composition and process of the proposed invention is furtherdescribed by the following examples which are intended merely foradditional description but are not limiting in any way.

EXAMPLE I

The following composition was prepared:

    ______________________________________                                                                 Percentage                                                                    by Weight                                            ______________________________________                                        Component A                                                                   Partially esterified styrene maleic anhydride (Pro 1100,                                                 34.4                                               Sartomer Co.)                                                                 Carboxylated acrylic copolymer (Carboset XPD-1042,                                                       23.8                                               B.F. Goodrich Co.)                                                            Multifunctional Acrylic monomer (SR 351, Sartomer Co.)                                                   2.5                                                Butadiene Nitrile Resin (Hycar CTBN 1300, B.F.                                                           4.8                                                Goodrich Co.).                                                                Photoinitiator (Acetophenone)                                                                            12.4                                               Aerosil R 974 (fumed Silica, Degussa, Co.)                                                               2.3                                                Epoxy Novolac Acrylate (CN 112C60,                                                                       16.3                                               Sartomer Co.)                                                                 Inert Divent               3.5                                                Component B                                                                   Multifunctional Epoxy Resin (ECN-1299, Ciba                                                              47                                                 Geigy Co.)                                                                    Epoxy Novolac Acrylate     51                                                 Filler                     2                                                  ______________________________________                                    

1. Application of Resist:

After preparation, the composition was mixed in proper proportion andcoated onto the surface of a cleaned and prepared copper coatedepoxy/glass laminate by means of Curtain Coating. The coating thicknesswas 1 mil (wet). The coated copper surface was then dried and imagewiseexposed to ultraviolet radiation in an amount of 200 watts per cm². Theexposed surface was then developed by spraying a solution of 10 gr/1potassium carbonate at 100° F. onto the surface, thereby selectivelyremoving the unexposed portions of the resist. Finally the remainingresist was further cured by baking at 300° F. for 1 hour.

2. Plating:

The surface was then plated using the following process:

    ______________________________________                                        Process Step     Time (min)                                                                              Temperature (°F.)                           ______________________________________                                        Solvent Swellant 3         110                                                Permanganate Etch                                                                              5         165                                                Permanganate Reducer                                                                           4         120                                                Condition        5         120                                                Copper Microetch 2         90                                                 Activate         5         90                                                 Accellerate      2         120                                                Electroless Metal Deposition                                                                   15        95                                                 Electrolytic Copper Flash                                                                      5         80                                                 Photo-Resist Application                                                      Pattern Plate Copper                                                          Pattern Plate Tin                                                             Strip the Photo-Resist                                                        Etch exposed Copper                                                           Strip Tin resist.                                                             ______________________________________                                         Note: Fresh water rinses were interposed betweeen chemical process steps      and at the end of processing.                                            

The adhesion of the plated metal to the permanent photodefinabledielectric surface was excellent. No blistering or peeling was observed.The adhesion of the metal to the surface was measured to be 4.8 lbs/in.In addition, the coverage of the surface with the plated metal wasexcellent. Substantially no voids in coverage were observed.

EXAMPLE II

Example I was repeated except that the butadiene nitrile resin was notincluded in the composition. The composition of component A wastherefore the following:

    ______________________________________                                                                   Percentage                                         Component A                by Weight                                          ______________________________________                                        Partially esterified styrene maleic anhydride (Pro 1100,                                                 34.4                                               Saromer Co.)                                                                  Carboxylated acrylic copolymer (Carboset XPD-1042,                                                       23.8                                               B.F. Goodrich)                                                                Multifunctional Aerylic Monomer (SR351, Sartomer Co.)                                                    7.3                                                Photoinitiator (acetophenone)                                                                            12.4                                               Aerosil R 974 (Degussa)    2.3                                                Epoxy Novolac Acrylate (CN112C60, Sartomer Co.)                                                          16.3                                               Inert Diluent              3.5                                                ______________________________________                                    

The results yielded poor adhesion of the plated metal to the permanentphotodefinable dielectric surface. Significant blistering and peeling ofthe metal from the surface was observed. The adhesion of the metal tothe surface was measured to be 0.5 lb/in. Because of the blistering andpeeling, coverage could not be evaluated accurately.

EXAMPLE III

Example I was repeated except that the photoinitiator was replaced witha sulfur bearing photoinitiator (Irgacure 907, Ciba Geigy Co.) at thesame concentration.

The results yielded poor coverage of the permanent photodefineabledielectric surface with the plated metal. Significant voids in theplating were observed. In addition a black smut was observed in thevoids and on the metal surfaces. Because of the significant voiding,adhesion could not be evaluated accurately.

EXAMPLE IV

Example I was repeated except that the fumed silica (Aerosil K 974,Degussa Co.) was replaced with amorphous silica at the sameconcentration.

The results yielded moderate adhesion. No significant blistering orpeeling was observed. The adhesion of the metal to the surface wasdetermined to be 3.0 lbs/in. In addition the coverage of the surfacewith the plated metal was excellent. Substantially no voids in coveragewere observed.

What is claimed is:
 1. A process for fabricating a circuitry package comprising:(a) Coating the surface of a substrate with a composition comprising:(1) at least one carboxy functional resin; (2) at least one acrylate oligomer; (3) at least one epoxy functional resin; (4) at least one butadiene nitrile resin; (5) at least one photoinitiator; and (6) at least one reactive monomer; (b) exposing the coating to an imagewise pattern of radiation, to which the composition is responsive, in an mount sufficient to at least partially cure the exposed areas of the composition; (c) developing the exposed composition with a solution which will selectively remove the non-exposed areas of the coating; (d) optionally, further curing the coating which remains on the surface; (e) optionally repeating Steps (a)-(d); (f) depositing a conductive material on at least those portions of the substrate which are not covered by the developed imagewise coating so as to form defined circuitry and interconnects; (g) optionally, repeating steps (a) through (f).
 2. A process according to claim 1 wherein the photoinitiator is a non-sulfur bearing photoinitiator.
 3. A process according to claim 2 wherein the butadiene nitrile resin is an epoxy terminated butadiene nitrile resin.
 4. A process according to claim 1 wherein the butadiene nitrile resin is an epoxy terminated butadiene nitrile resin.
 5. A process according to claim 1 wherein the composition also comprises a filler.
 6. A process according to claim 5 wherein the filler is fumed silica.
 7. A process according to claim 1 wherein the composition comprises:(a) from 2 to 50 weight percent of a carboxy functional resin; (b) from 20 to 50 weight percent of an acrylate oligomer; (c) from 20 to 50 weight percent of an epoxy functional resin; (d) from 1 to 10 weight percent of a butadiene nitrile resin; (e) from 2 to 15 weight percent of a photoinitiator; and (f) from 1 to 20 weight percent of a reactive monomer.
 8. A process according to claim 7 wherein the photoinitiator is a non-sulfur bearing photoinitiator.
 9. A process according to claim 7 wherein the butadiene nitrile resin is an epoxy terminated butadiene nitrile resin.
 10. A process according to claim 7 wherein the composition also comprises a filler.
 11. A process according to claim 10 wherein the filler is fumed silica.
 12. A process according to claim 7 wherein the reactive monomer is selected from the group consisting of multifunctional acrylates and multifunctional methacrylates.
 13. A process for fabricating a circuitry package comprising:(a) Coating the surface of a substrate with a composition comprising:(1) at least one carboxy functional resin; (2) at least one acrylate oligomer; (3) at least one epoxy functional resin; (4) at least one butadiene nitrile resin; (5) at least one photoinitiator; and (6) at least one reactive monomer; (b) exposing the coating to an imagewise pattern of radiation, to which the composition is responsive, in an amount sufficient to at least partially cure the exposed areas of the composition; (c) developing the exposed composition with a solution which will selectively remove the non-exposed areas of the coating; (d) optionally, further curing the coating which remains on the surface; (e) optionally repeating steps (a)-(d); (f) depositing a conductive material so as to form defined circuitry and interconnects upon the surface of the coating; (g) optionally, repeating steps (a) through (f) so as to build more than one layer of circuitry.
 14. A process according to claim 13 wherein the composition also comprises a filler.
 15. A process according to claim 14 wherein the filler is fumed silica.
 16. A process according to claim 13 wherein the composition comprises:(a) from 2 to 50 weight percent of a carboxy functional resin; (b) from 20 to 50 weight percent of an acrylate oligomer; (c) from 20 to 50 weight percent of an epoxy functional resin; (d) from 1 to 10 weight percent of a butadiene nitrile resin; (e) from 2 to 15 weight percent of a non-sulfur bearing photoinitiator (f) from 1 to 20 weight percent of a reactive monomer. 